Irving Zisman is the Jackass character played by Johnny Knoxville, a horny octogenarian here given his own spin-off movie that's only funnier than its trailer because it's longer. The Jackass movies and TV show are celebrated most for their outrageous stunts and set-pieces, and those are indeed their strongest assets; would that Knoxville and his collaborators on Bad Grandpa recognised a similar quality in this mostly improvised series of prank-pulling, as the harder they try, the better the results. That's supposedly contrary to achieving success in comedic improv, but if the filmmakers aren't trying to make you laugh with this stuff, what on earth are they trying to do instead? The vulgarity of Bad Grandpa's most outlandish skits is impressive, if quite tame by Jackass standards, while the hilarity is high. Scenarios featuring Irving's deceased wife are winners throughout, as are a trip to a strip club that just keeps surprising, a beauty pageant scene that defies belief, and a superbly grotesque fart joke moment in a restaurant. I'm not ashamed to be so amused by such puerility - shit, I'd be ashamed not to be. Knoxville's sharpness outweighs his flair, comedically, and his approach could benefit from being less academic and actually more adventurous, though he's pretty damn fearless as a performer. Child actor Jackson Nicoll actually outshines him, combining a natural and very appealing mischievousness with an unexpected comic professionalism for someone so young that's the most shocking thing about this film.